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3.2 BACKLIGHT UNIT
The back-light system is an edge - lighting type with a single CCFT ( Cold Cathode Fluorescent Tube ).
The characteristics of a single lamp are shown in the following tables.
ITEM
Lamp Current
Lamp Voltage
Frequency
Power Consumption
Operating Life Time
Startup Voltage
Note) The waveform of the inverter output voltage must be area symmetric and the design of the inverter
must have specifications for the modularized lamp.
The performance of the back-light, for example life time or brightness, is much influenced by the
characteristics of the DC-AC inverter for the lamp. So all the parameters of an inverter should be carefully
designed so as not to produce too much leakage current from high-voltage output of the inverter.
When you design or order the inverter, please make sure that a poor lighting caused by the mismatch of
the back-light and the inverter(miss lighting, flicker, etc.) never occur. When you confirm it, the module
should be operated in the same condition as it is installed in your instrument.
Note (1) Lamp current is measured with a high frequency current meter as shown below.
(2) Lamp frequency may produce interference with horizontal synchronous frequency and this
may cause line flow on the display. Therefore lamp frequency should be detached from the
horizontal synchronous frequency and its harmonics as far as possible in order to avoid interference.
(3) refer to I
X V
L
L
(4) Life time (Hr) of a lamp can be defined as the time in which it continues to operate under the
condition Ta = 25 ± 2°C and I
1. When the brightness becomes 50% or lower than it's original.
2. When the Effective ignition length becomes 80% or lower than it's original value.
(Effective ignition length is defined as an area that has less than 70% brightness compared to
the brightness in the center point.)
(5) The voltage above this value should be applied to the lamp for more than 1 second to startup
Otherwise the lamp may not be turned on.
Panel Specification
SYMB
MIN
3.5
I
L
-
V
L
45
f
L
P
-
L
H
2
0
0 ,
0
r
V
-
S
LCD
MODULE
No 2 Pin is V
LOW
X2CCFL to calculate.
= 6 mA
L
TYP
6.0
500
55
6.0
0
-
-
HOT : (PINK)
1
COLD : (WHITE)
2
A
1
HOT : (PINK)
COLD : (WHITE)
2
A
.
until one of the following event occurs.
rms
Ta=25 ± 2°C
MAX
UNIT
7.0
mA
rms
-
V
rms
70
KHz
-
W
-
H
o
r u
1000 (25°C)
V
rms
1300 (0°C)
INVERTER
NOTE
(1)
I
=6mA
L
(2)
(3), I
=6mA
L
(
) 4
(5)
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